Productivity And Nonspecific Resistance Of Broiler Chickens Under The Influence Of ?-carotene
L.V. Shevchenko, O.S. Yaremchuk, V.M. Mykhalska
Use in feeding broiler chickens of Vitaton and Vitadeps with and without butylhydroxytoluene (BHT) improves feed intake and water, and has no effect on body weight. The feeding of broiler chickens with mix fodder of Vitaton and BHT in doses that meet and exceed the physiological need of β-carotene calculated for retinol and Vitaton with no OSH in a normal dose of β-carotene did not significantly alter the absolute number of lymphocytes blood and the ratio of their subpopulation responsible for cellular (T-lymphocytes) and humoral (B-lymphocytes) immunity. Phagocytic activity of neutrophils and phagocytic index were not significantly changed in the peripheral blood of broiler chickens at feeding Vitaton as a source of β-carotene with/without BHT. Use of Vitaton without BHT in feeding of broiler chickens at a dose of 0.7 g/kg caused a lymphocytopenia. In chickens of this group we noted a decrease in the total number of lymphocytes in the blood due to decrease of cellular and humoral immunity, namely all subpopulations of T-lymphocytes, including T-helper cells - by 58.3 %, T-suppressors - by 41.0, T-helper cells active - at 43.5, B-lymphocytes by 60.1 %, and 0-lymphocytes – by 40.0 %. This is consistent with the reduction in titer of natural antibodies in their serum by 35.3 %. This phagocytic activity of neutrophils and index of phagocytes in blood of broiler chickens unchanged compared with the control. Use of Vitadeps in feeding broiler chickens at a dose of 5.6 g/kg in mix fodder also caused lymphocytopenia. This was reflected in the decrease of absolute number of blood 0-lymphocytes by 43.4 %, T-suppressors - by 38.7 % and T-helper cells active - by 39.0 %, but their ratio in the blood was like control level. Thus, usage of Vitaton and Vitadeps with/without butylhydroxytoluene in doses that meet the bird demands of β-carotene calculated to vitamin A, ensure the normal functioning of immune organs. Use of Vitaton with BHT as a source of β-carotene for the feeding of broiler chickens at a dose exceeding the normal content of vitamin A by 7 times, does not cause the violations of immunological homeostasis of the poultry. The Vitaton without butylhydroxytoluene and Vitadeps in doses exceeding the normal content of bird β-carotene calculated to vitamin A by 7 times depressing the immunopoesis in broiler chickens.